Processing of materials



Oct. 24, 1944. E. L. WIEGAND PROCESSING OF MATERIALS Original Filed Dec.7, 1939 w; %W W I L 3 f q 3 J. M iv a? M PROCESSING OF MATERIALS EdwinL. Wiegand, Pittsburgh, Pa., assignor to Orefraction Incorporated,Pittsburgh, Pa., a corporation of Pennsylvania Original applicationDecember 7, 1939, Serial No. 308,002. Divided and this applicationOctober 25, 1940, Serial No. 362,766

8 Claims.

My invention relates to the processing of materials, and moreparticularly, the conveying of materials, the grinding of materials, andthe eparation of co-mingled material particles. The principal object ofthe invention is the improvement of apparatus for carrying out suchprocessing of materials. This application is a division of myapplication Serial Number 308,002, filed December 7, 1939.

In the drawing accompanying this specification and forming a part ofthis application, there is shown, for purposes of illustration, oneembodiment of apparatus embodying the invention, and in this drawing:

Figure 1 is a more or less diagrammatic view of the relation betweenmaterial conveying means, grinding means, and separating means, as thesemeans may be utilized in one embodiment of my invention.

Figure 2 is a sectional view of a material hopper and control device,and

Figure 3 is an electrical diagram of a control circuit.

The term material i used herein to include any substance of a dividednature, as distinguished from relatively large blocks of substances. Theterm grinding is used herein in its broader aspects as meaning reductionin size, in any way, of the material being treated, and in its morespecific aspects, such grinding as occurs when material is subjected toimpact. EX- amples of material which may bFgro'iiiid by an apparatusembodying my invention are such materials as zircon, rutile, quartz,feldspar, fluorspar, marble, glass, enameling frit, hard metals,artificial or other abrasives, industrialldiamonds, and many otherseither of similar or different characteristics. The invention of thepresent application is shown as it may be used in connection with thereduction of, particularly, hard, tough, and abrasive materials,including ores having these characteristics. The illiistfati'ifembodimefitisparticularly adapted to grind material to ultra-fine sizes,such as for example 200 mesh to micron sizes, and in this embodiment thematerial to be ground preferably should not be larger than 16 to 18 meshsize, although it is possible to accommodate larger sizes. In

general the size to be commenced with in'this embodiment may be anydesirable size which cannot be better or more economically crushedotherwise, but since in this embodiment the material is projectedthrough a gun, the size of the material to be ground is related to gunsize, and therefore also to the capacity of the apparatus.

Referring to the schematic arrangement shown in Figure 1, the embodimentof the invention there illustrated comprises a container adapted tocontain material to be ground, and hereafter referred to as thenew-materials container. The new-materials container 50 may be formedwith an outlet spout 5| discharging into a funnel 52 carried by thereceiving end 53 of an elevating device 54, such as the bucket elevatorhere shown. Asuitable slide valve 55 is interposed in the outlet spout5| to regulate the flow of material from the new-materials container 50to the receiving end 53 of the elevator 54. The elevator. 54 may bedriven by means of an electric motor 56, and may also have a signaldevice, such as the electric light 51, to indicate when the elevator 54is op rating. The discharge end 58 of the elevator 54 ischarges into aconduit 59 leading to a blending and metering hopper 60, desirablyprovided with an inclined false bottom 6011 (Figure 2), and having highand low limit controls 6| and 62, so as to control operation of themotor 56 of the elevator 54, the connections being such that the motor56 of the elevator 54 is automatically started when the level of thematerial fall below the low level device 62, and the motor 56 isautomatically stopped when the material rises up to the high leveldevice 6|.

Preferably, the high level control 6| comprises a rotatable housingdisposed at the outside of the hopper 60, the housing containing amercury switch 645 (Figure 3). One terminal of the switch 645 isconnected to a conductor 660 leading to a source of electricity (notshown), the other terminal being connected to one terminal of the motor56. The other terminal of the motor 56 is connected, through a switch658, to a conductor 656 leading to the source of electricity. Thehousing BI is rotatable in one direction by a vane Gla within the hopper60 (see Figure 2). The low level device 62 comprises a pivoted vane6211, within the hopper 60, urged counterclockwise, as viewed in Figure2, by a counterweight 62b. The vanes 6Ia and 62a are shown in Figure 2in the position they occupy when the hopper 60 is full of material, aindicated by the upper dotted mound line M, the vane Bla standing about45 counterclockwise to the right of the vertical and the vane 62a about45 clockwise to the left of the vertical. The vanes 6Ia and 62a areshown as connected by a lost motion connection which includes a rod 620disposed at the outside of the hopper 60, pivoted at its lower end to acrank 62d movable in unison with the vane 62a, and having at its upperend a slot with which cooperates a pin on a crank 62e movable in unisonwith the vane am.

Withdrawal of the material from the hopper 60 causes the surface of themound of material to fall, but for the time being the vane 6la, byfriction adjustment of its shaft, remains in the position shown inFigure 2, even though the surface of the mound adjacent the vane Blarecedes away from that vane. When the mound of material decreases inheight so that its surface adjacent the vane 62a recedes sufiicientlyaway from that vane, the counterweight 62b causes counterclockwiserotation of the vane to a position about 45 counterclockwise to theright of the vertical, such movement being transmitted through the lostmotion connection so as to move the vane Gla clockwise to a positionabout 45 to the left of the vertical, thus moving the mercury switch 645to its on position, in which position it completes the circuit throughthe motor 56, whereby material is delivered to the hopper 60 by theelevator 54.

When the mound of material in the hopper increases, either by reason ofdelivery by the elevator 54 or otherwise, as will appear hereinafter,the material acts against the vane 62a and eventually moves the vane 62aclockwise, into the position shown in Figure 2, against the urgingaction of the counterweight, when the mound reaches the height indicatedby the lower dotted mound line 112. However, such movement of the vane62a will not affect the vane Bla because of the lost motion connectiontherebetween. When the mound of material rises enough, the material willact against the vane 6la and eventually move it counterclockwise to theposition shown in Figure 2, when the mound has increased to the upperdotted mound line M, thereby causing rotation of the mercury switch 645to its off position, and thus interrupting the circuit of the motor 56.

Positioned alongside of the receptacle 60 is a second elevator 63,having its inlet end 64 receiving material from the lower end of thehopper 60, as by means of a conduit 65, a suitable slide valve 66 beingso interposed as to control the amount of material flowing from thehopper 60. The elevator 63 is driven by an electric motor 61, and mayhave a signaling device, such as the electric light 68, to indicate whenthe motor 61 is running. The discharge end 69 of the elevator 63 leadsto the inlet of a solids valve 10 the outlet of which communicates withthe interior of a charge metering and hoist tank H. The hoist tank H hashigh and low level devices 12 and 13 respectively, so related to otherparts (as described in my aforesaid application) as to permit the motor61. to operate when the material is below the low level device 13, andto interrupt the circuit of the motor 61 when the material reaches thehigh level device 12.

A fluid under pressure, in the present instance, air, may be admitted tothe hoist tank 'll through a conduit 14, and such air may be releasedfrom the hoist tank H through either the conduit 14 or a blow-offconduit 15. With material in the hoist tank H, and air under pressuresupplied to the hoist tank H through the air conduit 14, the material inthe hoist tank H is forced to move into the lower end of a tube 2l9suitably connected at its upper end to and in communication with aconduit 16, the material continuing through the tube 2l9, through theconduit 16 to a connection conduit 11 between an air strainer tank 1.8and an upper material feed tank 19, a valve being interposed in theconnection conduit ,TI to permit admission of material to the upper tank19 and to enable the tank to be placed 2 2 fluid. PI9I binB'fi'i'ipo'sition, the material which passes through the conduit 1B isdelivered to the connection conduit 11, the ai r us e d f o r hg stip gpl ire -strained..bx. nmventesl..ire zz...th

flow of material from'the lower tank B L Means (not shown) is providedfor admitting air under pressure to the upper andlower tanksfl' and 8 I.

Assuming that the valve 83 is' 'cldsed'ahd"tlie valve 85 is open, and'assuming also that material is in the lower tank 8|, and that this tankis unwilllbe'forced through the outletconduittfl, and hr u a e. conduitmo. ehreaell ti on: gurf'88', and through this gun 88 to'the grinder"case-89, the material being projected from the muzzle of the gun in thegrinder case and subjected to impact in any desired way. The groundmaterial passes through a conduit 90 to a first separating device 9i ofthe cyclone type. 1% surfaces in the device 9| wh ig h mightbe subjectto abrasive weai iii aybe'siii'tably lined witlf rubber. Theheaviermaterial in'th'e first separating device 9| may gravitate through a tube5' against a check valve 92, this valve being so constructed andarranged that a predetermined head of material is built up andmaintained at the discharge end of the separating device 9|, materialbeing permitted to gravitate past the check valve, into the conduit 93,as further material accumulates in the discharge end of the separatingdevice- Any suitable check valve may be used and instances are describedin my aforesaid application. .The material then continues through theconduit 93 .to a funnel 94, and from the funnel 94 to a screen chamber95 of a screening device 96. j

The screening device 96 may be of the vibrating type, having a screen 91over which the material is shucked, the screen having a certainpredetermined mesh size, as for example 200 mesh.

The material which passes through the screen 9'! falls into a hopper 98,the outlet of the hopper 98 having a bagging device 99, to which a bagI00 is attached, the bag I00 receiving such material for shipment ifdesired. For convenience, the bag I00 may be disposed on a platform IOIof a scale I02, so that the amount of material delivered to the bag I00may be weighed as it is delivered to the bag. That material which doesnot pass through the screen 91 is discharged from the screen chamber 95through a conduit I03, and'back to the mixing hopper 60. Additionalmaterial, from the new-materials container 50, may be added to thehopper 60 by means of the elevator 54, the high level device 6| limitingthe amount of new material delivered to the hopper 60. In this mannerthe material removed from the system is automatically replaced With newmaterial from the new-materials Assuming the valve 90 to container 50.The slide valve 55 may be adjusted to a particular flow rate, such ratebeing determined by the rate at which finished material is removed fromthe system.

Additional separating means is provided for additionally separating thatmaterial which does not gravitate from the first separating device 9|,and this means comprises, among other parts, a pump, in this instance ablower fan I04, disposed within a fan chamber I and driven by anelectric motor I06. The outlet of the fan chamber I05 is branched, onebranch I0I leading to the atmosphere, and the other branch I08 beingconnected to one end of a conduit I09, the opposite end Il0 of theconduit I09 leading tangentially into the first separating device 9|, ifdesired in two diametrically disposed tangential branches H00. and H01).Slide valves III and I I2 are respectively interposed in the branchconduits I0! and I08, these valves being independently adjustable so asto regulate the amount of air discharged by the blowersthrough therespective branch, for a purpose to appear.

The upper discharge outlet of the separating device 9I is connected tothe inlet of the blower chamber I05, and in this instance certaindevices are interposed in this connection. Extending from the upperdischarge outlet of the first separating device 9! is a separatingcolumn, H3, of any suitable cross-sectional form, area, and length,which extends vertically and is connected to a conduit I M which istangentially connected to the upper end of a second air separatingdevice II6. Desirably the separating column II3 is enlarged with respectto the conduit H4, and may taper toward its lower end to cause hinderedsettling. The device II6 may be of the cyclone type, comprising achamber having an upper cylindrical portion I I1 and a downwardlytapering conical portion II8. A bagging device H9 is connected to thelower end of the conical portion H8, and has attached thereto a bag I20for receiving material gravitating downwardly of the conical portion H8.The upper end of the second separating device H6 is formed with ahousing I2I communicating with the interior of the device H6. Thehousing I2I communicates by means of a conduit I22 with a dust collectoror separator I23, which may be of any suitable type. The lower end ofthe dust separator I23 has attached thereto a bagging device I24, andthe air outlet of the dust separator I23 is connected by a conduit I25to the inlet of the fan chamber I05.

Assuming that the motor I06 is operating, and that the valve I I I is atleast partially open, and that ground material, along with air used ingrinding it, is being delivered through the conduit 90 to the firstseparating device 9|, the material which under the air conditionsprevailing in the separating system is not heavy enough to gravitate atonce from the separating device 9I, will be picked up by the stream ofair in the column II Some of this material will continue to be carriedby that stream to the top of the column II3 and through the conduit IMto the upper end of the second separating device H6, and will be causedto swirl in this upper end because of the tangential connection of theconduit H4. The heavier materials in the second separating device II6will gravitate downwardly through the conical portion II3, and will bedelivered to the bag I20 through the bagging device II9. The lightermaterial will be carried upwardly by the air stream through the housingI2I and the conduit I22, to the dust collector I23, where the dust willbe separated from the air, the dust particles being discharged from thebottom of the dust separator I23 and to the bagging device I24, and theair passing to the conduit I25 and back to the inlet of the blowerchamber I05. Some of the material which enters the separating column II3from the separating device 9I does not continue with the upwardly movingstream of air into the conduit 4, but gravitates back through the streaminto the separating device 9| and finally reaches the lower or dischargeend of the separating device 9I, and thus the separating action of thesystem is improved.

Depending upon the setting of the slide valves I I I and I I2, either anunder-pressure or an overpressure condition (with respect to atmosphericpressure) can be made to exist in the first separating device 9|.Usually the valve H2 is partially or completely closed, and the valve II I partially or completely open, so that an under-pressur or partialvacuum exists within the first separating device 9I and in the columnII3, whereby material readily passes from the grinder case 89 to thefirst separating device 9|, and no back pressure is created in theconduit 90 leading from the grinder case 89. Also, usually the valvesIII and H2 are adjusted to efiect substantially zero (atmospheric)pressure in the grinder case 89, thereby to avoid back pressure in thegrinder case 89 that might interfere with the operation of the grindergun. However, it will be apparent that the pressure conditions in thegrinder case and in the separating system can be regulated by adjustmentof the slide valves II I and H2 to obtain any desired pressureconditions. Furthermore, the velocity of the upwardly moving stream ofair in the separating column II3 may be adjusted to a most suitablevelocity so that the separating function of the column I I3 will beoptimum.

Since a certain head of material is maintained within the tube 5'II bythe valve 92, air communication between the conduits '93 and theinterior of the first separating device 9I is prevented. Thus thepressure condition within the device 9|, either greater or less thanatmospheric pressure, as may be desired, will not changed, since thecheck valve 92, either open or closed, substantially prevents flow ofair through the tube 51 I The first separating device 9| may be movedfrom the position shown in full lines in Figure 1 to the position shownin dotted lines, wherein its lower end no longer communicates with theconduit 93, but instead communicates with a conduit I35 leading to atank I36, hereinafter referred to as a by-pass tank. The lower end ofthe tank I36 carries a bagging device I31, to which a bag I38 may beattached, and a check valve I39 is interposed in the conduit I35, thecheck valve I39 being provided for the same purpose a the check Valve92. In this position of the device 9I, the ground material, exceptingonly a controllabl amount and size of very fine material, instead ofgoing to the screen chamber 95, passes directly to the by-pass tank I36.The conduit I I3 in this position may still be connected to the conduit4. The by-pass tank connection is particularly useful when it is desiredto make an unscreened ground aggregate, with only a minimum of extremefines removed.

The valve is closed. when initially charging the apparatus, and may alsobe closed for interrupting the process temporarily without relievedpressure on the lower feed tank 8|, or at the end of a run prior to asubsequent initial charging or beginning of operations. In other words,it is closed before initially charging, or at the end of a days run, orfor temporary interruption, and it is opened when beginning operations,as at the beginning of a day, or after an interruption as for inspectionor adjustment of other equipment.

While the material in the lower feed tank 8| is being ground, the hoisttank "II will have again been filled, with either new material or with amixture of new and partly ground material from overage from the screen96, and this charge will have been hoisted, and all is in readiness todump the same into the tank 8| when a low level responsive device (notshown) in the lower tank 8| indicates sufficient evacuation to receivethe next charge from the upper feed tank 19.

From the foregoing description of the apparatus and the operationthereof, it will be apparent that operation of the apparatus and processare enabled to be continuous, but interruptable when desired.

It will be evident that the illustrated apparatus embodies featureswhich are particularly applicable to the handling of finely dividedmaterial or dust, these features providing a closed system from which nodust can escape to the ambient air. It also will be evident that thoughcertain features are especially adapted for the handling of material ina grinding system and, more particularly, a continuous grinding system,the use of these features is not limited to either of these purposes.

From the foregoing it will be apparent to those skilled in the art thatthe disclosed apparatus embodying my invention provides a new andimproved apparatus for processing of materials, and accordinglyaccomplishes the principal object of my invention. On the other hand, italso will be obvious to those skilled in the art that the disclosedembodiment of my invention may be variously changed and modified, andfeatures thereof, singly or collectively, embodied in combinations otherthan that disclosed, without departing from the spirit of my inventionor sacrificing the advantages thereof, and accordingly, that thedisclosure herein is illustrative only, and that my invention is notlimited thereto.

I claim:

1. In means for feeding material to a grinding means; a tank; primarymeans for feeding material to said tank; means for conveying materialfrom said tank to the grinding means; means for separating a coarsefraction of material from the product of said grinding means; means forconveying said coarse fraction to said tank; and means for automaticallystarting and stopping said primary means in response to the amount ofmaterial in said tank.

2. In means for feeding material to a grinding means; a tank; primarymeans for feeding material to said tank; means for conveying materialfrom said tank to the grinding means; means for separating a coarsefraction of material from the product of said grinding means; means forconveying said coarse fraction to said tank; means for automaticallystarting and stopping said primary means in response to the amount ofmaterial in said tank; and means for controlling the rate at which saidprimary means while in operation feeds material to said tank.

3. In means for feeding material to a grinding means; a tank; primarymeans for feeding material to said tank; means for withdrawing materialfrom said tank and conveying it to the grinding means; means forcontrolling the rate of withdrawal from said tank; means for separatinga coarse fraction of material from the product of said grinding means;means for conveying said coarse fraction to said tank; means forautomatically starting and stopping said primary means in response tothe amount of material in said tank; and means for controlling the rateat which said primary means while in operation feeds material to saidtank.

4. In means for feeding material to a grinding means; a tank; primarymeans for feeding material to said tank; means for conveying materialfrom said tank to the grinding means; means for separating a coarsefraction of material from the product of said grinding means; means forconveying said coarse fraction to said tank; level responsive meanscomprising means responsive to a low level of material in said tank andmeans responsive to a high level of material in said tank; control meansmovable in response to said level responsive means; means whereby saidcontrol means controls said primary means; and said level responsivemeans being so constructed and arranged that said control means causesoperation of said primary means when the material in said tank decreasesto a predetermined low level and causes said primary means to continuein operation until the material in said tank increases to apredetermined high level and thereupon causes said primary means tocease operation until the material in said tank again decreases to saidpredetermined low level.

5. In combination: a tank for containing material to be ground; grindingmeans; primary means for feeding material to said tank; means forconveying material to said grinding means only from said tank; means forseparating a coarse fraction of material from the product of saidgrinding means; means for conveying only said coarse fraction to saidtank; and means for automatically starting and stopping said primarymeans in response to the amount of material in said tank.

6. In combination: a tank for containing material to be ground; grindingmeans; primary means for feeding material to said tank; means forconveying material to said grinding means only from said tank; means forseparating a coarse fraction of material from the product of saidgrinding means; means for conveying only said coarse fraction to saidtank; means for automatically starting and stopping said primary meansin response to the amount of material in said tank; and means forcontrolling the rate at which said primary means While in operationfeeds material to said tank.

7. In combination: a tank for containing material to be ground; grindingmeans; primary means for feeding material to said tank; means forwithdrawing material from said tank and for conveying to said grindingmeans only material so withdrawn; means for controlling the rate ofwithdrawal from said tank; means for separating a coarse fraction ofmaterial from the product of said grinding means; means for conveyingonly said coarse fraction to said tank; means for automatically startingand stopping said primary means in response to the amount of material insaid tank; and means for consponse to the amount of material in saidtank, said automatic means comprising, means responsive to low level ofmaterial in said tank, means responsive to high level of material insaid tank, control means movable in unison with said high levelresponsive means, and means whereby said low level responsive means isadapted to control said high level responsive means.

EDWIN L. WIEGAND.

